[R-pkg-devel] CRAN 'blackswan' server configuration

[Dirk Eddelbuettel]

As a long-time user of and advocate for 'ccache', I can attest that CMake has
good behaviour on its own: just tell it to use 'ccache' if found. There may
be more one than way, on a search I see '<LANG>_COMPILER_LAUNCHER' [1]. And
that is used in a simple pattern I have relied upon in the past:

   # Enable compiler cache to speed up recompilation
   find_program(CCACHE_FOUND ccache)

   if(CCACHE_FOUND)
     set_property(GLOBAL PROPERTY RULE_LAUNCH_COMPILE ccache)
     set_property(GLOBAL PROPERTY RULE_LAUNCH_LINK ccache)
   endif()

That should do the trick.

On the other hand, I found over the years that manually trying to replicate
and outsmart systems in the R package setup is not a winner as one tends to
end up in hard-to-debug corners such as the one you find yourself in. 

I do however always set 'ccache' in my own '~/.R/Makevars' and once every
thousand or two packages ('Rcpp' reverse depends let me compile a few)
something breaks because the package at hand does such local gymnastics,

So in short for your external libraries I would just try to tell CMake to
build a static library and to use 'ccache' if found.

Cheers, Dirk

[1] https://cmake.org/cmake/help/latest/prop_tgt/LANG_COMPILER_LAUNCHER.html

-- 
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